The present invention relates to wall plates of the type used to provide support, enclosure and decorative functions for wall-mounted wiring devices, such as switches and receptacles. More specifically, the invention relates to a two-piece wall plate having no exposed fastening devices, and providing improved features of both mechanical design and esthetic appearance.
Wall-mounted wiring devices such as switches and receptacles of various types are commonly constructed with a yoke or mounting strap having portions extending outwardly from opposite sides of the device. The device is mounted in a standard wall box by means of screws passing through openings in the extending portions of the yoke and received in threaded openings in the wall box. Such mounting may also ensure proper grounding of the device. The wall box is supported behind an opening in the wall such that the surface of the wiring device which is visible in its operative position is more or less flush with the wall surface. The installation is normally completed by mounting a wall plate upon the wiring device with operative portions of the device positioned within an opening in the plate, which covers the opening in the wall and the front of the wall box.
The wall plate is in most cases a relatively thin, rectangular, frame.TM.like member of plastic or metal. The most common means of mounting the wall plate is one or more screws passing through the plate and received in threaded openings in the body or yoke of the wiring device, with the screw heads visible on the exterior of the plate. A number of wall plate or other electrical cover plate designs have been proposed, however, wherein the fastening means are entirely enclosed and have no visible portions. These include, for example, the arrangements disclosed in U.S. Pat. No. 2,934,590 of Thomas et al, U.S. Pat. No. 3,155,808 of Wiley, U.S. Pat. No. 3,437,738 of Wagner, U.S. Pat. No. 4,359,619 of Bergoltz, U.S. Pat. No. 4,534,486 of Eidson and U.S. Pat. No. 4,731,511 of Steinhilber et al.
Although the typical wall plate is a single piece, e.g., a unitary molding or stamping, two-piece wall plate designs have been proposed. U.S. Pat. No. 4,833,277 of Jacoby, Jr., et al discloses a wall plate wherein an outer frame portion is attached to the wiring device by screws which remain visible on the outside of the plate, and a second plate is attached to the outer frame, within the opening defined thereby, by snap-fit or other connecting means. U.S. Pat. No. 4,835,343 of Graef et al discloses a two-piece wall plate wherein an inner plate is attached by screws to the wiring device yoke, and an outer plate is attached by snap-fit connectors on its lower surface to the inner plate, which has openings for receiving the connectors. There are no visible mounting or fastening means, and the inner plate is entirely covered by the outer plate upon complete installation. Also, the snap connection means are in the form of ears or tabs extending integrally from the rear side of the cover plate for insertion through slots in the base plate. The ears are thus subject to cracking or breaking.
It is a principal object of the present invention to provide a two-piece wall plate of novel and improved design for use with a wall-mounted electrical device, wherein portions of both pieces are visible in the fully installed condition, thus providing a hitherto unavailable range of decorating options.
Another object is to provide a wall plate for a wall-mounted electrical device wherein an outer or cover plate is attached by snap-fit connecting means to portions of an inner or base plate which extend through an opening in the cover plate.
A further object is to provide a two-piece wall plate for an electrical device wherein the configuration and manner of interconnection of a base plate and a cover plate ensure that the outer periphery of the cover plate, which encompasses the outside boundary of the base plate, firmly contacts the wall surface surrounding the device.
Still another object is to provide a two-piece wall plate for an electrical wiring device having improved means for snap-fit connection of the two pieces, reducing the possibility of cracking or breaking thereof.
Other objects will in part be obvious and will in part appear hereinafter.